MasterCard, the world's second-largest international credit card organization, is under an anti-monopoly investigation by the European Commission over its card transaction fees and commercial practices that might have violated the EU antitrust rules.

The move is part of the European Union’s efforts to combat cross-border trade barriers. If it is determined that MasterCard has violated the monopoly agreement, it may be subject to a fine of $740 million, equivalent to 10 percent of its 2012 revenue.

European Commission spokesman Antoine Colombani said on Tuesday that “the transaction cost paid by non-European cardholders making purchases in Europe is very high. The purpose of the survey is to ensure that consumers' interests will not be compromised.”

As well as inter-bank fees paid by cardholders from non-European Economic Areas (EEA) countries, the commission said the probe would look at rules that obliged merchants to accept all types of MasterCard cards, even if some of them incur higher charges.

According to Daily Economic News, the recent survey conducted by the European Commission will also involve other commercial practices by MasterCard such as its restrictions on merchants who wish to use banks outside their own country which are cheaper. The commission said that those practices may hinder e-commerce and cross-border trade.

In 2007, a similar probe led to the commission banning MasterCard from charging cross-border transaction fees within the European Economic Area.

MasterCard said it would fully cooperate with the investigation by the regulatory authorities and claimed that it has always committed to the balance of interests between consumers and merchants.

The commission said it would introduce regulations on credit card transaction fees and inter-bank fees to ensure fair competition by the middle of this year.